Field of the Invention
The present invention relates to a cooling structure of an electronic device such as a server, a host computer, and an industrial computer each equipped with a motherboard, a power source, and a cooling fan.
The present application claims priority on Japanese Patent Application No. 2012-48062, the content of which is incorporated herein by reference.
Description of the Related Art
Conventionally, electronic devices including power sources and electronic parts, serving as heat sources, need to be equipped with cooling fans for cooling heat sources. It is important for electronic devices, each including a plurality of electronic parts and a plurality of power sources (or power source units), to achieve a cooling structure for efficiently cooling heat sources.
Various technologies regarding cooling structures of electronic devices have been developed and disclosed in various documents. For example, Patent Literature 1 discloses a mounting structure of an electronic device including a plurality of logic units (e.g. CPUs), a plurality of power source units, and a plurality of fan units, wherein each power source unit is disposed in proximity to each logic unit. This technology aims to improve a cooling efficiency while preventing non-uniformity of power supply to each logic unit. Specifically, the housing of an electronic device is partitioned into a plurality of air passages, each of which allows cooling air to flow therethrough, wherein an air passage for each logic unit is separated from an air passage for each power source unit. Using each fan unit, cooling air is concurrently applied to air passages so as to cool each logic unit and each power source unit. However, the technology of Patent Literature 1 is disadvantageous because of its complex structure owing to the formation of air passages differently for each logic unit and each power source unit, which may increase the total weight of an electronic device.
Patent Literature 2 discloses an industrial computer chassis structure, which aims to optimize power supply to motherboards while reducing a power loss. The chassis shell (e.g. housing) of the industrial computer chassis structure is partitioned into various sections so as to mount a storage section, a fan section, a motherboard section, and a power source section in horizontally difference places. Herein, the power source section including a pair of power sources vertically combined together is disposed at the center position of the housing, while a pair of motherboards is horizontally disposed on both sides of the power source section; hence, the power source section is interposed between two mother boards, which are thus arranged as close to the power source section as possible. The fan section is located between the storage section and the motherboard section interposing the power source section. However, the technology of Patent Literature 2 may not demonstrate a good cooling effect when one power source additionally applies its heat to the other power source, thus totally increasing heat produced by a pair of power sources vertically combined together.
A server is one example of an electronic device including a plurality of electronic parts (e.g. CPUs) serving as heat sources. FIG. 6 is a plan view of a server 100 including a motherboard 101, a pair of CPUs 102, a housing 103, a plurality of fans 104, and a pair of power source units (or power supply units: PSU) 105. Herein, two CPUs 102 are mounted on the motherboard 101, while five fans 104 are aligned along the width direction of the housing 103. The intake side of each fan 104 is directed toward the width of the housing 103, while the outlet side of each fan 104 is directed toward each CPU 102. The two CPUs 102 are disposed in parallel with a predetermined gap therebetween and collectively disposed in the outlet direction of the fans 104 (i.e. the downstream direction of cooling air). Thus, it is possible to efficiently cool the CPUs 102 which are disposed in parallel and collectively exposed to a cooling air flow caused by the fans 104.
The server 100 has a redundant power source configuration using the two power source units 105 which may concurrently supply electric power to the CPUs 102. The server 100 is designed to adjacently dispose the two power source units 105 in a further downstream side of a cooling air flow compared to the CPUs 102.
In the server of FIG. 6, one CPU 102 and one power source unit 105 are positioned linearly along a cooling air flow; hence, a cooling air flow caused by the fan 104 is temporarily warmed by heat caused by the CPU 102 and subsequently flows into the power source unit 105. This may degrade a cooling effect for the power source unit 105 in the server 100.
Due to the adjacent arrangement of the power source units 105, one power source unit 105 additionally applies its heat to the other power source unit 105. This may further degrade a cooling effect for the power source units 105.
In order to adequately cool the power source units 105 in the server 100, it is necessary to increase the speed of rotation of the fans 104 or the internal fans (not shown) embedded in the power source units 105, thus improving an airflow rate with the fans 104 or the internal fans (hereinafter, collectively referred to as cooling fans). Alternatively, it is necessary to increase the number of fans 104 or to use high-performance fans for the server 100. This may increase the cost price of the server 100. Moreover, this may entail unnecessary limitation to the size and capacity of the server 100 so as to prevent an increase in a heating value of each power source unit 105